Friday, December 25, 2015

SAMSUNG DVD – HD860 Power supply circuit - ICE3B0365


Off-Line SMPS Current Mode Controller with integrated 650V Startup Cell
The new generation CoolSET-F3 provides Active Burst Mode to reach the lowest Standby Power Requirements <100mW at no load. As the controller is always active during Active Burst Mode, there is an immediate response on load jumps without any black out in the SMPS. In Active Burst Mode the ripple of the output voltage can be reduced <1%. Furthermore, to increase the robustness and safety of the system, the device enters into Auto Restart Mode in the cases of Overtemperature, VCC Overvoltage, Output Open Loop or Overload and VCC Undervoltage. By means of the internal precise peak current limitation, the dimension of the transformer and the secondary diode can be lowered which leads to more cost efficiency. An adjustable blanking window prevents the IC from entering Auto Restart or Active Burst Mode unintentionally during high load jumps. The CoolSET-F3 family consists a wide power class range of products for various applications.
Pin Functionality
SoftS (Soft Start & Auto Restart Control)
The SoftS pin combines the functions of Soft Start during Start Up and error detection for Auto Restart Mode. These functions are implemented and can be adjusted by means of an external capacitor at SoftS to ground. This capacitor also provides an adjustable blanking window for high load jumps, before the IC enters into Auto Restart Mode.
FB (Feedback)
The information about the regulation is provided by the FB Pin to the internal Protection Unit and to the internal PWM-Comparator to control the duty cycle. The FBSignal controls in case of light load the Active Burst Mode of the controller.
CS (Current Sense)
The Current Sense pin senses the voltage developed on the series resistor inserted in the source of the integrated Depl. CoolMOS. If CS reaches the internal threshold of the Current Limit Comparator, the Driver output is immediately switched off. Furthermore the current information is provided for the PWMComparator to realize the Current Mode.
Drain (Drain of integrated Depl. CoolMOS)
Pin Drain is the connection to the Drain of the internal Depl. CoolMOS
VCC (Power supply)
The VCC pin is the positive supply of the IC. The operating range is between 8.5V and 21V.
GND (Ground)
The GND pin is the ground of the controller.
The oscillator generates a fixed frequency. The switching frequency of ICE3Axx65x is fOSC = 100kHz and for ICE3Bxx65x f OSC = 67kHz. A resistor, a capacitor and a current source and current sink which determine the frequency are integrated. The charging and discharging current of the implemented oscillator capacitor are internally trimmed, in order to achieve a very accurate switching frequency. The ratio of controlled charge to discharge current is adjusted to reach a maximum duty cycle limitation of Dmax=0.72.
Control Unit
The Control Unit contains the functions for Active Burst Mode and Auto Restart Mode. The Active Burst Mode and the Auto Restart Mode are combined with an Adjustable Blanking Window which is depending on the external Soft Start capacitor. By means of this Adjustable Blanking Window, the IC avoids entering into these two modes accidentally. Furthermore it also provides a certain time whereby the overload detection is delayed. This delay is useful for applications which normally works with a low current and occasionally require a short duration of high current.